Stack-type oil bath filter



Filed July 28, 1949 u mm Mm Tm 0am m V a m n K 4 M 1 .c f a 7 M l m a EE Patented May 13, 1 952 2,596,121 STACK-TYPE OIL BATH FXLTER Jacob K.Brixius, Cleveland, Ohio, assignor to Air-Maze Corporation, Cleveland,Ohio, a corporation of Delaware Application July 28, 1949,SerialN0.'107,255

8 Claims. 1

This invention relates to improvements in a stack-type oil bath filter.

One of the objects of the present invention is to provide an improvedtype of filter wherein the entering stream of dirty gas or air passesdownwardly through a central tube, then impinges against an oil bath inacup, then flows radially outwardly in all directions and upwardlythrough a mass of wires or similar material which serves the doublepurpose of catching the dirt on oil washed surfaces and also preventingthe carrying of oil droplets out the exit.

Another object of the'present invention is the control of the oil as itis addedto the air stream at several points along its path of travel sothat the gaseous stream to be cleaned is thoroughly saturated with. theoil but not to a degree where oil is carried past the outlet.

Still another object of the invention is the provision of a manometertype of control for the oil in the bowl at the base of the filter soficient device and one which is easily cleaned,

but which is fool-proof in the hands of the usual operator.

.Other objects and advantages of the present invention will be apparentfrom the accompanying drawings and description and the essentialfeatures will be summarized in the appended claims.

In the drawings, Fig. l is a View of one ernbodiment of my device takenalong the line I-i of Fig. 2 and wherein the left-hand portion of Fig.

1 isa central sectional View and the right-hand portion is asideelevational view;

fig. 2:is.a top plan view of the device of .Fig. 1; Fig. 3 is a.fragmental sectional view taken along the line 3--3 of Fig. l;

Fig. 4 is a view illustrating one type of screen element which issuitable for use in my improved filter; while Fig. 5 is a iragmentalsectional view similar to a portion of Fig. 1 and showing a modifiedconstruction.

Referring now to Fig. -1, I have-shownone form of my device as embodyinga top sub-assembly it, an intermediate sub-assembly H, a bowlsubassembly i2 and a bafile sub-assembly I3 The top sub-assemblycomprises an outer cylindrical housing forming an upper housing part Lll, open at the bottom and closed at the top by the annular plate it. Acentral tube lfiextendsdownwardly through the annular plate and providestheinlet for the dirty gaseous stream tobecleaned. Preferably, theannular plate it has an upturned flange [5a. which is secured as bywelding to the tube It. Near the top of the housing 14 and at one sidethere is provided an outlet nozzle "l1 which communicates with theinterior of the housing It. Just below the level of the outlet l i isprovided a layer ie-of filter material. This layer is preferably of aforaminous material providing a great many wires producing a mazethrough which the mixed'stream-of gas, dirt and oil particles must workits way upwardly toward the outlet ll. One form of material which issuitable for filling'the layer is, is a foraminous screen mesh materialsuch asdisclosed in United States Patent No. 2,190,683 granted to AlbertE. Schaaf et a1. February 20, 1940. Such a screen layer is illustratedin Fig. i -havingthe same depth as the layer IE which may be formed fromconcentric strips constructed as shown or may be rolled upon itselfspirally until the layer It: is complete to the annular depth required.As shown in Fig. 4, one layer of the screen material has corrugationslta extending at an angle to the vertical while the adjacent layer hascorrugations Ito which extend at an angle "to the corrugations 18a so asto prevent nestingoi adjacent layers. Astaught'in the above mentionedSchaaf et a1. patent, a single strip of screenma- 'terial may be foldedalong its upper edge We so as to provide this construction if desired.Another manner of providing a foraminous screen mesh material which issuitable for the layer it is shown in the copending application 5 OliverH. Schaaf, SerialNo. 760,320, filed July of the plate is cut out asshown at ieb to provide iv openings for the flow of gaseous stream. Thisleaves an internal ring Ito which has a slight clearance from thecentral tube It. A plurality of webs I9d extend between the internalring I9c and the outer rim so as to provide the necessary strength. Thelower rim of the housing I4 is flaredoutwardly as shown at I ia so as toaid.

in securing the housing It to the member below it.

The intermediate assembly I I comprises an outer, generally cylindricalwall forming a lower housing part 20 and an inner tube 2i which fitstelescopingly outside of the lower end of tube It. A plate 22 providedwith perforations 22a similar to the perforations shown at I92) has adownwardly extending peripheral flange 2219 which is welded at its upperportion to the lower end of the cylindrical member 26. A layer of filtermaterial 23 similar in construction to that shown at I8 rests upon theplate 22a. and upon radially extending'ribs of the same similar to theribs Iiid g,-

of Fig. 3. The upper side of this layer is contained by means of a plateZilc which in the present instance is integral with the member 26 butwhich might be a separate plate if desired and Welded to the member 2!).This is provided with openings 20d similar to the openings 22a to permitthe free flow of gaseous stream upwardly. A flange 286 is turnedupwardly at the inner edge of the plate 280 and is welded to the tube 2Iat its upper end. The material of the cylindrical wall member 20 is bentoutwardly at 26] to provide an outwardly extending rib and is then bentinwardly to provide a trough at 289 for the purpose of retaining acircular O-ring 23' which ex tends entirely around the cylindricalmember 23 resting in the trough 26 A clamping ring 2 3 then extendsentirely around the members I and I I at their junction. This ring 2:;has a concave inner face which rests upon the flange Ida of the memberI4 and also beneath the rib 20 of the member 26. A screw 25 pulls twoears 2 a. of the band 24 together so as to clamp the ring 314 tightly inplace in a well known manner.

The bowl member I2 is of cup-shape opening upwardly and is provided withgenerally cylindrical side walls I; and a bottom I212. The side wallsI2a are preferably marked at a level above the bottom at the desirablelevel for filling with oil. The mark in the present instance is providedwith the inturned bead I20. The bowl member is secured to theintermediate assembly I l by a pair of clamps 26 arranged diametricallyopposite each other. Each clamp comprises a. stifi" wire Eta loopedthrough a suitable opening in a trough 2'5 which is integral with theside wall 21! of the intermediate member II. In the lower end of thewire is provided a hook-shape portion b which engages a helicalcompression spring 28 which is housed inside of a downwardly opening cup-shape thimble 260. The lower end of the thimble is provided with a noseor projection 28d which en-' gages in a recess H20 in the bottom of thebowl. The thimble 260 is provided with finger grips Zte by which theclamp may be manipulated. The

l upper edg of the bowl is flared outwardly as indicated at I2d and anO-ring 29 rests in the space between the wall 22b, the trough 2'! andthe flared flange I2d as clearly shown at the left-hand side of Fig. 1.The clamps 26 are then pulled downwardly against the tension of springs23 and the noses 2601 are engaged beneath the bottom wall of the bowl sothat the bowl is held tightly to the intermediate assembly II.

Inside of the bowl is the battle sub-assembly it. This comprises agenerally imperforate double cup member 3E3 which is secured as byWelding at 3I to a skirt member 32. This skirt member is a generallycylin'dricalbaifieextending to a point near the bottom I22) and having aradially outwardly extending flange 32a at its upper end adapted to restupon the bead I2c of the bowl. This is the sole support for the cup 3tand the skirt 32 and holds all of the parts at th proper level andcentered within the bowl structure. A plurality of openings 32b throughthe flange 32a permit a free flow of oil at this point.

The double cup member 36 comprises two concentric and connected cupportions. A smaller cup portion has generally cylindrical side walls 39aof a diameter slightly less than the diameter of tube 2! and animperforate bottom 3812. A larger cup portion has a radially extendingbottom 360 which extends outwardly from the top of the cylindrical wall553a being connected therewith by a smooth curve. This bottom wallextends outwardly to the skirt 32 and to the securing point 3ipreviously mentioned. The wall of the larger cup portion then extendsupwardly terminating in a generally cylindrical portion 38d whichextends to a vertical cylindrical rim at a point somewhat above thebottom of the tube .EI and above the flange 32a. A plurality ofrelatively small openings 39c are arranged in a circle around the bottomtile. Preferably, these openings are provided by punching tongues 36)upwardly acting as bafiles and extending radially V which is preferablyof a coarse hardware cloth of the order of three or four meshes perinch. The member 33 is formed in a generaly domeshape having its upperinner edge resting on a slight shoulder Zia formed wher the tube 2Iflares slightly outwardly near the end of tube it. The lower outer endof the foraminous member 33 touches the cylindrical wall 221) and rests.upon the lip 3% of the double'cup member 3c.

The operation of my invention should now be apparent. The bowl i2 isfirst fllled with oil to the liquid level indicated at A, Fig. 1, asindicated by the bead I20. Throughout the specification and claims, Ihave used the term oil'to mean any suitable liquid, adhesive which maybe carried by the air stream up intothe filter elements I8 and 23tocatch the dirt particles in the gaseous stream and to wash the sameback into the bottom of the bowl. The filter is usually mounted in aposition where a gaseous stream will be drawn into the inlet tube It anddischarged at the outlet tube H. .A common use of this filter is inconnection with an internal combustion engine where the suction at thedischarge end flows downwardly through the tube [6 which is telescopedinto the tube 2| as shown so that the flow continues to the bottom ofthe tube 2| where it then turns radially outwardly in all directionsmoving freely and smoothly over the curved surface 2| 1; whichterminates in an out-turned flange 2 lo. Any heavy dirt particles comingdown the central tube will strike the oil in the smaller cup portion36a, 3% so that'a great dealof this material will be retained there. Thedepth of the cup is so proportioned that the oil will not be entirelyblown out of the smaller cup portion a, 30b bythe flow of air at therated velocity. The oil level will therefore drop to the dot-dash line Bindicated in the small cup. At the same time, the diiTerential pressureabove and below the annular opening 34 will cause the oil level in theouter annular chamber to be raised to the level of the dot-dash line Cof Fig. 1, and the level in the chamber 35 inside of the skirt 32 willdrop to the level of line D there indicated. In other words, thechambers 35 and 35 are a manometer with the two legs separated by theskirt-32. The level D is just slightly below the bottom wall portion 380and the air streaming at high velocity radially outwardly over thetongues 30 induces a slight flow of oil through the openings 30a in thedirection of the small arrow of Fig. 1. Some of the oil displaced fromthe bowl I2 is carried upwardly by the air stream and thoroughly coatsthe foraminous wire screen mesh material in the filter elements l8 and23. However, these elements are so arranged and contain such a maze ofwires that no oil droplets are carried to the outlet ll. Dirt particlesnot caught in the striking of the oil in the smaller cup at the base oftube 2 I, are carried upwardly, mingled with oil and trapped in thefilter elements I8 and 23 and washed back downwardly by the continuousflow of oil which goes on. Due to the arrangement of the flange or lip2|c there is a quiescent zone at 31 just above this lip and adjacent theouter wall of tube 2|. There is another quiescent zone at 33 just abovethe annular chamber 35. This permits oil returning downwardly from thefilter elements to drain down alongside the tube 2| and to drip off theflange or lip 2|c into the upcoming stream. Other oil comes down theouter wall of the cylindrical wall 233 and down along the member 22 toreturn to the chamber 35. Some of this oil will drip over into theupcoming air stream at the zone 39. The wires of the screen 33 permitother oil dropping down intermediate the tube 2| and the Wall 2219 to becarried radially outwardly and downwardly along the wires 3| to bereturned to the chamber 35.

In a modified form of my construction, illustrated in Fig. 5, the deviceis made in two parts instead of three as in the case of the device ofFig. 1. In the device of Fig. 5, the parts I5, l6, IT, IS and is) arethe same as in the first described form. The cylindrical wall portion l4extends entirely down the length of the filter material sections l8 and23 to terminate just above the flange Me. The lower bowl or oilreservoir .0 has a cylindrical wall a which fits telescopingly outsidethe lower portion of member 14. Here a "rubber :ring 29' is held'between the bead 4| on member Mandthe'lipdllb of the lower bowl 40. Thelower end of the central 'tube 2l" is telescopingly connected to thelower end of tube -|6 as in the first described form. In addition, clips42 hold these parts assembled. If desired, this "end portion 2| could bemade i'n tegral with tube H5. The perforated wall portion 43 extendsacross the top of the filter element 23 and iswelded to cylindrical wall44 w'hich extends downwardly along the inside of wall I4 of the housing,terminating a littlebelow the :rim 48 in an inturned fiange 44a. Thesheet of'coarse screen material 33' is in all respects analogousto themember 33 of the first described form. Its outer edge rests on flange44a. The receptacle 45 is a double cup member like 30 having a smallercup portionllla which always retains some oil. Several openings 46permit return of -oil from the chamber D to the reservoir of-oil inside0! 45a. The receptacle 45 has anout-turned'edge flange 45?) which restson the shoulder 40c. Several openings 41 permit fiow of oil from theannular space E downwardly. A cylindrical partition i8 extends upwardlyfrom the larger cup portion of receptacle 45 as an'extensionof the cupand terminates in a vertical cylindrical rim48'. In this form of mydevice, when the clamps 2B are released, the lower portion comes awayfor cleaning and servicing bringing the lower tube portion 2| with it sothat it is easily cleaned. Theparts ilia and M come apart at theseal 29.In "other respects the device of Fig. 5 functions like the device ofFig. 1.

It will be noted in Fig. 5 that a partition has been omitted inthe'position of thepartition 320i Fig. 1. This partition in Fig. 1 formsa manometer-like arrangement so that the oil inside of the partition issubjected to the higher pressure of the inlet air stream and the oiloutside of the partition is subject to air under lesser pressure at thezone (it. Thus, the column of oil outside of the partition 32 up to thetop of the rim 3| at the zone 39 forms seal preventing the leakage ofair downwardly through openings 33c and through the oil bath andupwardly outside of the rim 3|. In Fig. 5 this partition similar to 32has been omitted. Instead the rim 3%? has been extended upwardly to thezone 38 sufficiently to maintain a column of oil outside of thepartition 48 which is of great enough depth to prevent-the leakage orbypassing of oil downwardly through the openings in reservoir a belowthe baflle 46 and thence outwardly through the oil bath and upwardlyoutside of the rim of the larger cup portion of the double cup member 45and outside of the rim 48.

It is important to the functioning of my filter that the parts beproperly proportioned. The cross-sectional area of the central inlettube Iii with relationship to the cubic feet per minute of dirty airentering the device is critical. I find that the cross-sectional area ofthe central tube It should measure in square inches betweenone-twenty-fifth and one-fortieth of the rated capacity of the filterfor air volume rated in cubic feet per minute. I find that the bestresults occur when the cross-sectional area of the inlet tube in squareinches is one-thirtieth of the air volume handled in cubic feet perminute.

I find another critical relationship in the volume of oil betweenthelevel A and the bottom 30c and the bottom of the smaller cup portion3012. This volume which -I shall hereafter call "the central "volume hasa critical relationship with times the peripheral volume.

.Fig. 1.

what I will hereafter call the peripheral volume. This is the volume inthe annular space between one and one-half and two times the peripheralvolume and the best results are obtained when the central volume is oneand three-quarters t results from this proportioning of the parts thatwhen the device is in action, some of the oil beneath the level A in thecentral volume is forced outwardly up to the level of the line C to fillthe peripheral volume and the excess oil capacity goes up to wet thefilter elements it and 23 together with the moving oil in action. Itshould be understood that throughout the entire discussion of thissubject, there is always a pool or reservoir of oil above the bottom 39bof the smaller cup portion up to approximately the level indicated bythe dot-dash line B of I find that by proportioning the area of thecentral inlet tube to the air capacity as described above and byregulating the amount of oil in the device in the central volume ascompared to the peripheral volume, I can maintain this pool or reservoirof oil in the central cup at the rated capacity of the unit.

The rules as to the proportioning or the various parts, as set forth inconnection with the embodiment of Fig. 1, should also be applied to theform shown in Fig. 5. The cross sectional area of the central inlet tubeIS should be held in the same relationship to the cubic feet per minuteof dirty air entering the device. The central volume of oil between thenormal oil level line A of Fig. ,5 and the two bottoms of the larger andsmaller cup portions of the receptacle 45 should be between one andone-half and two times the peripheral volume as represented by theannular space E between the line A and the level of the rim 48. If theserules are followed, there will always be a pool of oil in the lowerreservoir 45a of the receptacle 45 when the device is in action.

When the filter of Fig. is being utilized at its, rated capacity, theoil in the central volume is' reduced below the normal level A down to alow point in the reservoir 35a and this oil goes to fill the peripheralvolume E and also fills up the filtering elements it and 23 and becomespart of the oil in action also.

What I claim is:

1. In a liquid washed filter, the combination of a generally cylindricalhousing positioned with its axis vertical, top and bottom wallssubstantially closing said housing, an inlet for a dirty gaseous streamcomprising a tube positioned axially of said housing, said tube leadinginto the top of said housing and terminating at its mouth above thebottom wall of said housing, there being an outlet from said housingnear the top thereof, a double cup member in said housing and spacedbelow the mouth of said tube, said cup member having larger and smallerconcentric connected cup portions with the smaller cup portion depressedbelow the larger cup portion, the bottom of said larger cup portionextending radially outwardly from the upper!. edge or said smaller cupportion and then turning upwardly sald rimending ate level above themouth or said tube, there being spaced openings extending through thebottom of one of said cup portions,

.bafiles above said openings inclined outwardly and upwardly, animperiorate cylindrical partition wall forming a skirt generallyconcentric inside said housing and extending from said rim to a pointnear the bottom wall of said housing, two portions of foraniinous filtermaterial spanning the annular space between said tube and said housingabove the mouth of said tube and below said outlet, there being an openspace between said tube and said housing between said filter portions,and normal oil level indicia at a level just below the mouth of saidtube.

2. The combination of claim 1 wherein the central volume of oil betweensaid normal oil level and the bottoms of said larger and smaller cupportions is between one and one-half and two times the peripheral oilvolume measured in the annular space between said skirt and said housingand between said normal oil level and the level of the top of said rim.

3. In a liquid washed filter, the combination of a generally cylindricalhousing positioned with its axis vertical, top and bottom wallssubstantially closing said housing, an inlet for a dirty gaseous streamcomprising a tube positioned axially of said housing, said tube leadinginto the top of said housing and terminating at its mouth above thebottom wall of said housing, there being an outlet from said housingnear the top thereof and independent of said inlet tube, a double cupmember in said housing concentric below the mouth of said tube, said cupmember having larger and smaller concentric connected cup portions withthe smaller cup portion depressed below the larger cup portion, saidsmaller cup portion forming a reservoir, the bottom of said larger cupportion extending radially outwardly from the rim of said smaller cupportion, the upper rim of said larger cup portion being spaced inwardlyfrom said housing, said bottom of said larger cup portion being lowerthan the mouth of said tube and said rim being spaced radially outwardlyfrom the mouth of said tube, there being spaced openings extendingthrough the bottom wall of one of said cup portions, foraminous filtermaterial spanning the annular space between said tube and said housingabove the mouth of said'tube and below said outlet, and normal oil levelindicia at a'level just below the mouth of said tube.

4; The combination of claim 3 including a shee of coarse foraminousmaterial below said filter material and extending from said tube, closeto said filter material, outwardly and downwardly to the side wall ofsaid housing at approximately the level of said rim. 1

5. The combination of claim 3 wherein said spaced openings extendingthrough the bottom wall of one of said cup portions are provided in thebottom wall of said smaller cup portion, and bailles above said openingsinclined outwardly and upwardly.

6. The combination of claim 3 wherein said spaced openings extendingthrough the bottom wall of one of said cup portions are provided in thebottom wall of said larger cup portion, and baffles above said openingsinclined outwardly and upwardly.

'7. The combination of claim 3 wherein said housing has an upper partand a lower part, said filter material has an upper portion carried by 7said upper housing part and alower portion car- 'm-ried by said lowerhousin part, said tubing has a lower portion carried by said lowerhousing REFERENCES CITED part and a separable fluid tight connection Thefollowing references are of record in the tween said lower and upperhousing parts, wherefile of this patent: by said lower housing part maybe removed, carrying with it said lower tube portion. 5 UNITED STATESPATENTS 8. The combination of claim 3 wherein the Number Name Datecross-sectional area of said central inlet tube 2,062,548 Wilson Dec. 1,1936 measured in square inches is between th and 2,171,752 Kamrath Sept.5, 1939 4 th of the rated air capacity of said filter meas- 2,342,447Bennett et a1 Feb. 22, 1944 ured in cubic feet per minute. 10 2,387,278Lowther Oct. 23, 1945 JACOB K. BRIXIUS.

